G'day bigtwin. I have a 2014 build TP which I bought in 2015. It now has 29,430kms up and it uses 100cc/1000km of oil.
I have run various grades of oil, but I used only semi-synthetic in the initial 20,000kms before changing to full syn.
I used 15w50, tried 20w50, and at 15,000kms put Motul 10w50 5100 in. I think the engine just uses more oil up till 15,000kms as it takes forever to fully run in and seal up.
You can't go wrong with 15w50, but I recommend Motul 5100 with a change every 5,000kms or if you can afford it M300v 15w50.....that's good stuff that will go 10,000kms if your motor is fully run in and ready for the best of the best full synth oil.
I'm about to book in for my 30,000km service if it will stop raining on weekends and let me do the last 450kms........ I will try Motul 7100 20w50 (currently using M7100 10w60 which is also very good for fully run-in motors).
If your airbox is filling up with oil it will have nothing to do with 10w40 etc - there was a recall for an airbox mod that I have read about on the 2014-16 forum.
One last point - be very accurate with oil level checks - there are a lot of wankers arguing about technique, but if you put your Capo on the centre stand AFTER a proper ride, you will get an accurate hot oil level reading after 3-5mins. This should be between the marks, but usually closer to the top mark (in fact right on the max mark after a service!).
Hope this helps - it is possible the guys have been tricked into overfilling the big lump, so always hot check on the same level spot after a long ride......